Various medical devices can non-invasively measure physiological parameters of a patient. Some of these devices include pulse oximetry devices and electroencephalogram (EEG) measurement devices, among others. An example is the BIS™ brain monitoring system from Covidien LP (Boulder, Colo.). These devices can measure pulse, breathing rates, brain activity, or other parameters experienced by the patient during various medical procedures, such as surgery and subsequent recovery.
Patient pain levels during sedation can be difficult to quantify and measure due to the subjective nature of pain, as well as due to a consciousness level of the patient. In some medical procedures the patient receives anesthesia or other conscious pain reduction treatments, which can include unconsciousness, amnesia, analgesia, and muscle relaxation, which make quantification and measurement of pain levels difficult. Furthermore, patient-to-patient variation in pain response and the possibility of subjectivity in nociception pain response measurements make pain response measurements difficult.
Some physiological measurement techniques, such as EEG measurements, can provide an indication of a current level of brain activity, and corresponding depth of anesthesia, experienced by a patient, but do not identify a pain response of that patient. Capacitive sensing has been employed to measure some physiological parameters by applying electric fields to the tissue of the patient. However, this capacitive sensing merely measures parameters such as pulse rate of a patient for blood perfusion and oxygen saturation measurements.
Overview
Systems, methods, sensors, and software for providing enhanced measurement and detection of patient pain response are provided herein. In a first example, a measurement system is provided that includes a capacitive system configured to measure a capacitance signal for tissue of the patient. The measurement system also includes a patient monitor configured to measure an electrical signal representing brain activity of the patient. The measurement system also includes a processing system configured to determine pain metrics based at least on the capacitance signal and the electrical signal, and determine a pain response of the patient based at least on the pain metrics and pain calibration information for the patient.
In a second example, a method of operating a measurement system to detect pain response in a patient is provided. The method includes measuring a capacitance signal of tissue of the patient using a capacitive sensor proximate to the tissue of the patient, measuring an electrical signal representing brain activity of the patient, and determining a pain response of the patient based at least in part on pain metrics derived from the capacitance signal, the electrical signal, and pain calibration information for the patient.
In a third example, an apparatus is provided. The apparatus includes one or more computer readable storage media, and program instructions stored on the one or more computer readable storage media for at least identifying a pain response in a patient. When executed by a processing system, direct the processing system to at least monitor a capacitance signal of tissue of the patient using at least one capacitor element applied to the tissue of the patient, process the capacitance signal to derive one or more capacitive pain metrics for the patient, identify an electrical signal representing brain activity of the patient, and determine the pain response of the patient based at least on correlating the electrical signal to the capacitive pain metrics.